Neurology- Pathology Flashcards
What are the main causes of dementia (marked by a decrease in cognitive ability, memory, or functioning with intact consciousness)?
- Alzheimer disease
- Frontotemporal dementia
- Lewy body dementia
- Creutzfeldt- Jakob disease
- Other
What pts are most at risk for Alzheimer?
elderly and Down syndrome pts.
What mutations mediate risk for Alzheimer?
ApoE2: decrease risk
ApoE4: increases risk
APP, presenilin-1, presenilin-2: increased risk of early onset
What are the main findings of Alzheimer’s?
widespread cortical atrophy
narrowing of the gyri and widening of sulci
decreased ACh
Senile plaques (below) in gray matter
Neurofibrillary tangles
What are senile plaques?
extracellular B-amyloid cores that may cause amyloid angiopathy leading to intracranial hemorrhage (AB amyloid synthesized by cleaving amyloid precursor protein (APP))
What are Neurofibrillary tangles?
intracellular, hyperphosphorylated tau protein (insoluble cytoskeletal elements). No of tangles correlates to the severity of disease
What is frontotemporal dementia (aka Pick disease)?
frontotemporal atrophy (spares parietal lobe and posterior 2/3 of the superior temporal gyrus) causes marked by dementia, aphasia, parkinsonian aspects, and change in personality
What are these?
Pick bodies: silver staining spherical tau protein aggregates
What is Lewy body dementia?
initially dementia and visual hallucinations followed by parkinsonian features
What causes Lewy body dementia?
a-synuclein defect (Lewy bodies, primarily cortical)
What is Creutzfield-Jakob disease?
rapidly progressive (weeks to months) dementia with myoclonus (“starte myoclonus)
What is myoclonus?
Myoclonus is a brief, involuntary twitching of a muscle or a group of muscles. It describes a medical sign and, generally, is not a diagnosis of a disease.
These myoclonic twitches, jerks, or seizures are usually caused by sudden muscle contractions (positive myoclonus) or brief lapses of contraction (negative myoclonus). The most common circumstance under which they occur is while falling asleep (hypnic jerk).
Myoclonic jerks occur in healthy persons and are experienced occasionally by everyone. However, when they appear with more persistence and become more widespread they can be a sign of various neurological disorders. Hiccups are a kind of myoclonic jerk specifically affecting the diaphragm. When a spasm is caused by another person it is known as a provoked spasm. Shudderingattacks in babies fall in this category.
Other features of Creutzfeldt-Jakob disease?
spongiform cortex affected
prions present
What are some other causes of dementia?
multi-infarct (aka vascular, 2nd most common cause of dementia in the elderly)
syphillis, HIV
vitamin B1, B3, or B12 deficiency
Wilson disease
normal pressure hydrocephalus
What is MS?
Autoimmune inflammatory and demyelination of the CNS (brain and spinal cord)
When is MS common to present initially?
more common in white living further from the equator
women in their 20-30s
How does MS present?
can present with:
optic neuritis (sudden loss of vision resultin in Marcus Gunn pupils)
INO
hemiparesis
hemisensory symptoms
bladder/bowerl incontinence
all with a remitting and relapsing course
What are the lab findings of MS?
increased CSF protein (IgG)
Oligoclonal bands are diagnostic
The gold standard for MS diagnosis is an MRI. How does it appear?
preiventricular plaques (area of oligodendrocyte loss and reactive gliosis) with destruction of axons
How is MS tx?
slow progression with disease-modifying therapies (e.g. B-interferon, natalizumab).
Tx acute flares with IV steroids
Symptomatic tx for neurogenic bladder (catheterization, muscarinic antagonists), spasicity (baclofen), pain (opiods)
What is acute inflammatory demyelinating polyradiculopathy?
the most common subtype of Guillian-Barre syndrome, and is an autoimmune condition that destroys Schwann cells causing inflammation and demyelination of peripheral nerves and motor fibers
How does acute inflammatory demyelinating polyradiculopathy present?
symmetric ascending muscle weakness and/or paralysis beginning in lower extremities
may see autonomic dysregulation (e.g. cardiac irregularities, HTN or hypotension) or sensory abnormalities
What is the prognosis for acute inflammatory demyelinating polyradiculopathy?
almost all survive and the majority recover completely after weeks to months
What are the lab findings of acute inflammatory demyelinating polyradiculopathy?
increased CSF protein with normal cell count (may cause papilledema)
What are some associations with acute inflammatory demyelinating polyradiculopathy?
infections (viral, Campylobacter)- autoimmune attack of peripheral myelin due to molecular mimicry
Tx of acute inflammatory demyelinating polyradiculopathy?
respiratory support is critical until recovery
additional: plasmapheresis, IV immunoglobulin
What are some other demyelinating and dysmyelinating diseases?
- Acute disseminated (postinfectious) encephalomyelitis
- Charcot- Marie-Tooth disease
- Krabbe disease
- Metachromatic leukodystrophy
- Progressive multifocal leukoencephalopathy
- adrenoleukodystrophy
Describe Acute disseminated (postinfectious) encephalomyelitis
multifocal perivntricular inflammation and demyelination after infection (commonly measles or VZV) or certain vaccinations (e.g. rabies, smallpox)